arch/powerpc/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ARCH_POWERPC_UACCESS_H
   3 #define _ARCH_POWERPC_UACCESS_H
   4
   5 #include <asm/ppc_asm.h>
   6 #include <asm/processor.h>
   7 #include <asm/page.h>
   8 #include <asm/extable.h>
   9
  10 /*
  11  * The fs value determines whether argument validity checking should be
  12  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  13  * get_fs() == KERNEL_DS, checking is bypassed.
  14  *
  15  * For historical reasons, these macros are grossly misnamed.
  16  *
  17  * The fs/ds values are now the highest legal address in the "segment".
  18  * This simplifies the checking in the routines below.
  19  */
  20
  21 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  22
  23 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
  24 #ifdef __powerpc64__
  25 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  26 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
  27 #else
  28 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  29 #endif
  30
  31 #define get_fs()        (current->thread.addr_limit)
  32
  33 static inline void set_fs(mm_segment_t fs)
  34 {
  35         current->thread.addr_limit = fs;
  36         /* On user-mode return check addr_limit (fs) is correct */
  37         set_thread_flag(TIF_FSCHECK);
  38 }
  39
  40 #define segment_eq(a, b)        ((a).seg == (b).seg)
  41
  42 #define user_addr_max() (get_fs().seg)
  43
  44 #ifdef __powerpc64__
  45 /*
  46  * This check is sufficient because there is a large enough
  47  * gap between user addresses and the kernel addresses
  48  */
  49 #define __access_ok(addr, size, segment)        \
  50         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  51
  52 #else
  53
  54 static inline int __access_ok(unsigned long addr, unsigned long size,
  55                         mm_segment_t seg)
  56 {
  57         if (addr > seg.seg)
  58                 return 0;
  59         return (size == 0 || size - 1 <= seg.seg - addr);
  60 }
  61
  62 #endif
  63
  64 #define access_ok(addr, size)           \
  65         (__chk_user_ptr(addr),          \
  66          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  67
  68 /*
  69  * These are the main single-value transfer routines.  They automatically
  70  * use the right size if we just have the right pointer type.
  71  *
  72  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  73  * and yet we don't want to do any pointers, because that is too much
  74  * of a performance impact. Thus we have a few rather ugly macros here,
  75  * and hide all the ugliness from the user.
  76  *
  77  * The "__xxx" versions of the user access functions are versions that
  78  * do not verify the address space, that must have been done previously
  79  * with a separate "access_ok()" call (this is used when we do multiple
  80  * accesses to the same area of user memory).
  81  *
  82  * As we use the same address space for kernel and user data on the
  83  * PowerPC, we can just do these as direct assignments.  (Of course, the
  84  * exception handling means that it's no longer "just"...)
  85  *
  86  */
  87 #define get_user(x, ptr) \
  88         __get_user_check((x), (ptr), sizeof(*(ptr)))
  89 #define put_user(x, ptr) \
  90         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  91
  92 #define __get_user(x, ptr) \
  93         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  94 #define __put_user(x, ptr) \
  95         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  96
  97 #define __get_user_inatomic(x, ptr) \
  98         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
  99 #define __put_user_inatomic(x, ptr) \
 100         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 101
 102 extern long __put_user_bad(void);
 103
 104 /*
 105  * We don't tell gcc that we are accessing memory, but this is OK
 106  * because we do not write to any memory gcc knows about, so there
 107  * are no aliasing issues.
 108  */
 109 #define __put_user_asm(x, addr, err, op)                        \
 110         __asm__ __volatile__(                                   \
 111                 "1:     " op " %1,0(%2) # put_user\n"           \
 112                 "2:\n"                                          \
 113                 ".section .fixup,\"ax\"\n"                      \
 114                 "3:     li %0,%3\n"                             \
 115                 "       b 2b\n"                                 \
 116                 ".previous\n"                                   \
 117                 EX_TABLE(1b, 3b)                                \
 118                 : "=r" (err)                                    \
 119                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 120
 121 #ifdef __powerpc64__
 122 #define __put_user_asm2(x, ptr, retval)                         \
 123           __put_user_asm(x, ptr, retval, "std")
 124 #else /* __powerpc64__ */
 125 #define __put_user_asm2(x, addr, err)                           \
 126         __asm__ __volatile__(                                   \
 127                 "1:     stw %1,0(%2)\n"                         \
 128                 "2:     stw %1+1,4(%2)\n"                       \
 129                 "3:\n"                                          \
 130                 ".section .fixup,\"ax\"\n"                      \
 131                 "4:     li %0,%3\n"                             \
 132                 "       b 3b\n"                                 \
 133                 ".previous\n"                                   \
 134                 EX_TABLE(1b, 4b)                                \
 135                 EX_TABLE(2b, 4b)                                \
 136                 : "=r" (err)                                    \
 137                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 138 #endif /* __powerpc64__ */
 139
 140 #define __put_user_size(x, ptr, size, retval)                   \
 141 do {                                                            \
 142         retval = 0;                                             \
 143         switch (size) {                                         \
 144           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 145           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 146           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 147           case 8: __put_user_asm2(x, ptr, retval); break;       \
 148           default: __put_user_bad();                            \
 149         }                                                       \
 150 } while (0)
 151
 152 #define __put_user_nocheck(x, ptr, size)                        \
 153 ({                                                              \
 154         long __pu_err;                                          \
 155         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 156         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 157                 might_fault();                                  \
 158         __chk_user_ptr(ptr);                                    \
 159         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 160         __pu_err;                                               \
 161 })
 162
 163 #define __put_user_check(x, ptr, size)                                  \
 164 ({                                                                      \
 165         long __pu_err = -EFAULT;                                        \
 166         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 167         might_fault();                                                  \
 168         if (access_ok(__pu_addr, size))                 \
 169                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 170         __pu_err;                                                       \
 171 })
 172
 173 #define __put_user_nosleep(x, ptr, size)                        \
 174 ({                                                              \
 175         long __pu_err;                                          \
 176         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 177         __chk_user_ptr(ptr);                                    \
 178         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 179         __pu_err;                                               \
 180 })
 181
 182
 183 extern long __get_user_bad(void);
 184
 185 /*
 186  * This does an atomic 128 byte aligned load from userspace.
 187  * Upto caller to do enable_kernel_vmx() before calling!
 188  */
 189 #define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
 190         __asm__ __volatile__(                           \
 191                 "1:     lvx  0,0,%1     # get user\n"   \
 192                 "       stvx 0,0,%2     # put kernel\n" \
 193                 "2:\n"                                  \
 194                 ".section .fixup,\"ax\"\n"              \
 195                 "3:     li %0,%3\n"                     \
 196                 "       b 2b\n"                         \
 197                 ".previous\n"                           \
 198                 EX_TABLE(1b, 3b)                        \
 199                 : "=r" (err)                    \
 200                 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
 201
 202 #define __get_user_asm(x, addr, err, op)                \
 203         __asm__ __volatile__(                           \
 204                 "1:     "op" %1,0(%2)   # get_user\n"   \
 205                 "2:\n"                                  \
 206                 ".section .fixup,\"ax\"\n"              \
 207                 "3:     li %0,%3\n"                     \
 208                 "       li %1,0\n"                      \
 209                 "       b 2b\n"                         \
 210                 ".previous\n"                           \
 211                 EX_TABLE(1b, 3b)                        \
 212                 : "=r" (err), "=r" (x)                  \
 213                 : "b" (addr), "i" (-EFAULT), "0" (err))
 214
 215 #ifdef __powerpc64__
 216 #define __get_user_asm2(x, addr, err)                   \
 217         __get_user_asm(x, addr, err, "ld")
 218 #else /* __powerpc64__ */
 219 #define __get_user_asm2(x, addr, err)                   \
 220         __asm__ __volatile__(                           \
 221                 "1:     lwz %1,0(%2)\n"                 \
 222                 "2:     lwz %1+1,4(%2)\n"               \
 223                 "3:\n"                                  \
 224                 ".section .fixup,\"ax\"\n"              \
 225                 "4:     li %0,%3\n"                     \
 226                 "       li %1,0\n"                      \
 227                 "       li %1+1,0\n"                    \
 228                 "       b 3b\n"                         \
 229                 ".previous\n"                           \
 230                 EX_TABLE(1b, 4b)                        \
 231                 EX_TABLE(2b, 4b)                        \
 232                 : "=r" (err), "=&r" (x)                 \
 233                 : "b" (addr), "i" (-EFAULT), "0" (err))
 234 #endif /* __powerpc64__ */
 235
 236 #define __get_user_size(x, ptr, size, retval)                   \
 237 do {                                                            \
 238         retval = 0;                                             \
 239         __chk_user_ptr(ptr);                                    \
 240         if (size > sizeof(x))                                   \
 241                 (x) = __get_user_bad();                         \
 242         switch (size) {                                         \
 243         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 244         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 245         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 246         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 247         default: (x) = __get_user_bad();                        \
 248         }                                                       \
 249 } while (0)
 250
 251 /*
 252  * This is a type: either unsigned long, if the argument fits into
 253  * that type, or otherwise unsigned long long.
 254  */
 255 #define __long_type(x) \
 256         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 257
 258 #define __get_user_nocheck(x, ptr, size)                        \
 259 ({                                                              \
 260         long __gu_err;                                          \
 261         __long_type(*(ptr)) __gu_val;                           \
 262         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 263         __chk_user_ptr(ptr);                                    \
 264         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 265                 might_fault();                                  \
 266         barrier_nospec();                                       \
 267         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 268         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 269         __gu_err;                                               \
 270 })
 271
 272 #define __get_user_check(x, ptr, size)                                  \
 273 ({                                                                      \
 274         long __gu_err = -EFAULT;                                        \
 275         __long_type(*(ptr)) __gu_val = 0;                               \
 276         __typeof__(*(ptr)) __user *__gu_addr = (ptr);           \
 277         might_fault();                                                  \
 278         if (access_ok(__gu_addr, (size))) {             \
 279                 barrier_nospec();                                       \
 280                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 281         }                                                               \
 282         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 283         __gu_err;                                                       \
 284 })
 285
 286 #define __get_user_nosleep(x, ptr, size)                        \
 287 ({                                                              \
 288         long __gu_err;                                          \
 289         __long_type(*(ptr)) __gu_val;                           \
 290         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 291         __chk_user_ptr(ptr);                                    \
 292         barrier_nospec();                                       \
 293         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 294         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 295         __gu_err;                                               \
 296 })
 297
 298
 299 /* more complex routines */
 300
 301 extern unsigned long __copy_tofrom_user(void __user *to,
 302                 const void __user *from, unsigned long size);
 303
 304 #ifdef __powerpc64__
 305 static inline unsigned long
 306 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 307 {
 308         return __copy_tofrom_user(to, from, n);
 309 }
 310 #endif /* __powerpc64__ */
 311
 312 static inline unsigned long raw_copy_from_user(void *to,
 313                 const void __user *from, unsigned long n)
 314 {
 315         if (__builtin_constant_p(n) && (n <= 8)) {
 316                 unsigned long ret = 1;
 317
 318                 switch (n) {
 319                 case 1:
 320                         barrier_nospec();
 321                         __get_user_size(*(u8 *)to, from, 1, ret);
 322                         break;
 323                 case 2:
 324                         barrier_nospec();
 325                         __get_user_size(*(u16 *)to, from, 2, ret);
 326                         break;
 327                 case 4:
 328                         barrier_nospec();
 329                         __get_user_size(*(u32 *)to, from, 4, ret);
 330                         break;
 331                 case 8:
 332                         barrier_nospec();
 333                         __get_user_size(*(u64 *)to, from, 8, ret);
 334                         break;
 335                 }
 336                 if (ret == 0)
 337                         return 0;
 338         }
 339
 340         barrier_nospec();
 341         return __copy_tofrom_user((__force void __user *)to, from, n);
 342 }
 343
 344 static inline unsigned long raw_copy_to_user(void __user *to,
 345                 const void *from, unsigned long n)
 346 {
 347         if (__builtin_constant_p(n) && (n <= 8)) {
 348                 unsigned long ret = 1;
 349
 350                 switch (n) {
 351                 case 1:
 352                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 353                         break;
 354                 case 2:
 355                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 356                         break;
 357                 case 4:
 358                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 359                         break;
 360                 case 8:
 361                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 362                         break;
 363                 }
 364                 if (ret == 0)
 365                         return 0;
 366         }
 367
 368         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 369 }
 370
 371 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 372
 373 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 374 {
 375         might_fault();
 376         if (likely(access_ok(addr, size)))
 377                 return __clear_user(addr, size);
 378         return size;
 379 }
 380
 381 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 382 extern __must_check long strnlen_user(const char __user *str, long n);
 383
 384 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 385                 unsigned size);
 386 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
 387                            size_t len);
 388
 389 #endif  /* _ARCH_POWERPC_UACCESS_H */